


The little Tsuna-fish

by AmbroiseFramboise



Category: Katekyou Hitman Reborn!
Genre: Alternate Universe - Supernatural Elements, Cannibalism, Demigods, Kinda, Merpeople, Priests, Vampires
Language: English
Status: In-Progress
Published: 2018-01-28
Updated: 2018-05-03
Packaged: 2019-02-27 19:41:45
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 4,246
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13255278
Author URL: https://archiveofourown.org/users/AmbroiseFramboise/pseuds/AmbroiseFramboise
Summary: In this story, Iemitsu's nickname for Tsuna is nearer from the truth than he ever thought.Aka the universe where Tsuna is half-merman, and there is more impossible things than ever happening in Nanimori. But no-one really cares. Some things are different, other don't change. Reborn is Reborn after all, and Nanimori was always a bit weird anyway.





	1. Chapter 1

**Author's Note:**

> There might be some mistakes with the orthograph or the construction of the sentences, but I'm not English and I don't have a beta. You can point them if you find some, and I'll try to correct it.
> 
> The updates won't be regular I'm sorry.
> 
> Thank you for reading !
> 
> A-F

Once upon a time, there was a lovely mermaid named Nana. She fell in love with an human. It happened from time to time so there was a potion for that, like in the famous story. Only, to keep the mermaid from dying, it just exchanged their tail for legs. Permanently.

So Nana, in love, on two legs and with a enchanting voice met Iemitsu. After a whirlwind romance, they were married and she was pregnant. Their child was named Tsunayoshi by his father (and his mother, later, in the secret of the night, gave his a mermish one.)

Then he left to work, first only some days, the for weeks, months, and finally years. Nana wasn’t really bothered, it wasn’t uncommon for mermen to leave for long periods of time. She knew he loved her and it was enough. (Tsuna didn’t have the same opinion.)

He would never know how ironic the nickname “Tuna-fishie” was. The little boy had the powerful tail and the scales of… a red tuna. Nana almost laughed herself sick the first time she heard it.

But she was great at acting so she didn’t. All merpeople were, their kind was made for seduction after all. She wasn’t nearly as oblivious as she looked.

She also knew of her husband line of work (she had done her research) but she couldn’t care less. Her kind was made of warriors, life in the sea wasn’t as easy as it looked. There were dangers and predators everywhere.

The first time she saw him, she was still a mermaid, curious about humans, and he was with a team of people in suits, directing them as they disposed of a body in the sea. Nana thought it was a great gift and ate it with gusto. 

The aftertaste left by the strange (probably magical) flames was delicious.

Yes they ate human bodies. They could be hard to find in those times with the whole “keep our existence secret” thing. The merpeople weren’t like those in the Disney movie. Well they could be if they wanted to, but the old sailor tales were mostly true. They would attract people in the water with their beautiful bodies and songs (mildly hypnotics), drown them and eat their corpses.

This taste for human didn’t disappear when she got her permanent legs. So maybe there was less criminals than there was before… well it was Hibari territory.

OoOoOoOoOoOoOoOoOoOoOo

Little Tsuna grew up in a body that wasn’t exactly right. He had balance problems and kept falling. But when he was in the water, everything was right. Legs fused to form a silver tail and gills opened. Bath time was welcomed and it was a nightmare to get him out. Otherwise Tsuna was a sweet little thing, shy but kind, small and cute with big brown eyes full of laughter and wonder.

One day, during one of his Papa’s visits when he was five, something happened. Grandpa Nono looked normal and had a kind smile but the half-merman boy was uneasy. He should have known better than try to climb a tree to get his ball. 

He fell and fire, orange fire like his father’s appeared in is hands. If only it hadn’t ! Now the fire was gone and he was cold inside. It was as if his human part was sealed off. 

When he told it to his mother after the men left, he saw her angry for the first time. She was scary, pointed teeths and nail-claws. Her hair was flying around her face and she was hissing furiously in an unknown language. She only stopped when a small hand tugged at her sleeve. 

“That’s scary Mama !” cried Tsuna.

“Oh dear, I’m sorry baby. Shh, don’t cry Mama isn’t angry at you. Dry your tears my sweet, you are leaving pearls everywhere. Do you want to hear more stories about my family in the sea ? I can teach you our language and some easy songs ro start if you want. Would you like that ?” she apologized, taking him in her arms.

“Yes please !” he answered with a little smile as she took his cheek in her hand. Then they found all the pearl-tears, round and shiny and gathered them in a velvet pouch, with the others. 

Tus started the mermish education of a young Tsuna. To celebrate, she cooked him human meat for the first time that night. He loved it.

OoOoOoOoOoOoOoOoOoOoOoOoO

The thing is, Tsuna’s flames came from his human side, the one he got from his father. Merpeople didn’t usually have this kind of magic. They were closely linked with it and by suppressing them, well … it was harder to act human, to copy perfectly their behaviour. 

Somehow, kids could sense that, and it subconsciously scared them (like herbivores with a predator hidden in their mist). So they reacted, they lashed out. And the bullying started. After all, he was small, shy, alone and friendless. He never retaliated, he was too kind for that. 

One could think that for someone like him, who saw human as prey and ate their flesh regularly at dinner, beating bullies would be easy. But he had listened to his Mama’s lessons, and one of the most important things was that children were precious and fragile. He was stronger physically but he had no real control and could break them easily. 

So he didn’t react. It wasn’t as if it hurt a lot, his skin (scales) was tough and he knew some simple healing songs, good for little scratches and the lot.

OoOoOoOoOoOoOoOoOoO

(The main Rules, that he learned early were :

-Don’t reveal what you are, or your powers.  
-Don’t go after children or pregnant women for meat, and if possible go after criminals and those who wouldn’t be missed.  
-Don’t eat your friends, it’ll be hard to find new ones if they keep dying mysteriously around you. And it’s suspicious.  
-Be kind to other supernatural or mystical beings but be careful not to anger them.  
-Avoid a maximum using the seduction/hypnotism/control powers until you are older, particularly on adults.)

OoOoOoOoOoOoOoOoOoO

Some of the Rules were easy for now. It was his mother that did all the hunting (even if she taught him how to cook), he didn’t know any other supernatural beings than his mother (and she never let him go to the midnight meetings that took place from time to time) and he didn’t have any friends. Little did he know, it would soon change. 

Nanimori was a strange place. 

Politically it was neutral (but under the rules of the Hibari Clan), and a perfect place for ex-mafiosi who wanted a peaceful place to retire or raise children. Spiritually, with at least a hundred little temples and two big official ones, plus one of the Earth Magical vein traversing the city, it was truly full of magic.

It showed in it’s apparence. The nature was far more green than it was elsewhere, the water was clearer. Sometimes, there was some mysterious mist in places there shouldn't, like in the middle of the day, only in a specific alleyway. People learned young to turn a blind eye to it if they weren’t concerned. It was someone else’s problem after all.

And there was little to no risks of those irregularities being shared with the rest of the world. Tourists were strangely blind (few had the capacities to even see half of the city), and quick to leave. Even if they talked, who would believe them ? There was no material evidence to prove their claims. When someone from outside married a native, they would experience it little by little, and lean to live with it. Those not liked by the town never stayed long anyway. 

But the Nanimori liked being lively, that’s why there was so many mafiosi, retired or not. Particularly those strong enough to have Dying Will’s flame. Common or not, they were still a form of magic, just one accessible by some human. It helped that they were usually more perceptible and apt at spotting the strangeness of the city. And that they never said no to a little action once in a while, retirement could be quite boring. The rest of the populace was weird too and they could be part of the mob without fearing standing out. 

Yes Nanimori was an interesting place. She even had her favorites children. Though it might be more a curse than a blessing sometime. The life of Tsunayoshi Sawada and his friends were a perfect exemple.


	2. Chapter 2

**Summary for the Chapter:**

> The little Tsuna makes his first friend !

**Notes for the Chapter:**

> It took me a long time to complete this, I'm sorry. (I got distracted by my others stories)
> 
> As always, I may have made some mistakes, I don't have a beta. If you see one, you can point it to me. 
> 
> Hope you like it, and thanks for reading ! 
> 
> A-F

Tsuna made his first friend when he was nine. The other boy was named Yamamoto Takeshi, and his dad was the owner of the best sushi shop of the city. That’s how they really met ; they may be in the same school, and have the same age, but they were in different classes. Plus, Yamamoto was in the baseball club, and the center of the group thanks to his talent. He had an approachable personality and a big smile, and that made him popular.

So the boys never talked before that evening. 

But Nana, as human as she looked, still liked fish very much, particularly raw. (They might eat humans, but it wasn’t their principal diet. Merpeople ate a lot of fish in the sea, and other meats when they could, with a side of seaweed.) Tsuna too was fond of sushi and sashimis.

It was a friday night, but they were the last customers. It was late, they had finished their meal, and the adults had started discussing about some thing or another. Apparently, the Yamamoto’s line was made of priests, and even if they left at some point, they always came back to take care of their minor shrine. It was just after their backward, next to one of the rivers ; made for the god of Water and Rain, a local deity. 

Tsuna was sitting on a stool, playing with some string, when he saw on the other side of the counter a little brown haired boy, a bit familiar. He wasn’t one of those that tormented him, he probably never insulted him either. So the shy half-merman kid waved at him with a small smile when the other met his eyes. He was immediately rewarded with a big grin. 

The adults watched them with amusement, and pushed them toward each other. It was the perfect occasion for them to make a friend, a true one, who knew about the magical side of Nanimori. Both close to water in their nature, and without reason to distrust each other, the parents had agreed that their meeting would be a great idea. 

“Hello there ! I’m Takeshi ! Do you like sushi ?” asked the taller of the two boys.

“H-hi ! I’m Tsuna, and I love it !” answered Tsuna, blushing in embarrassment. He was unused to social interaction but eager to talk to someone that looked so friendly. 

“Takeshi, Tsuna is one of the “special people”, so why don’t you boys go play in the backward while we adults talk about boring things ?” said Tsuyoshi, his eyes warm as he ruffled his son’s hair.

“Special ? What kind ? Dad and I are priests ! Well I’m not one yet, but I’ll be ! Are you a youkai ? What sort ?” A torrent of questions left Takeshi’s mouth, as he move back and forth on his heels.

“Slower dear, he doesn’t have the time to answer. My little Tsuna is a bit shy.” said Nana, chuckling in her hand, looking quite pleased with herself.

“I-I’m not really a youkai, I’m a merman. Well, an half, my dad is human. But I can still turn in one in the water, and I swim very fast !” tried to explain Tsuna. He didn’t totally understand the differences between species of supernatural being yet, but he knew that youkai wasn’t the right word.

“Youkais are for those whose species originate from Japan. However, my clan was from the Mediterranean sea. Now go, or you won’t have the time to play.” said Nana, before turning back to the counter, where Tsuyoshi was cleaning his knives.

“Okay !” they exclaimed.

The two boys looked at each other, and Takeshi lead them to the door, still talking animatedly, apparently about fishes. 

“Don’t worry, there is nothing dangerous near our shrine, and I already asked to the God to protect my son, and his friends if needed.” casually said the man, watching the door where their boys had disappeared. 

“Oh, I don’t worry much, we’re from Water too, and my baby can take care about himself for most of the time. He’s more afraid about hurting others. He doesn’t tell me, but I can see how he refuse to react when bothered by normal children.” 

“Takeshi is stronger than them, and I’m pretty sure they are going to play a variant of baseball anyway. He loves that sport.” 

“In the dark ? We can see well at night, it’s needed in the deeper parts of the ocean, but humans usually can’t, right ?”

“Oh, there will be some light. Candles on the shrine, and firefly around the river.”

“Well, you know better than me. I swear, sometimes I have troubles finding whether or not it’s normal to act a certain way for humans. They are still a lot of things that make no sense for me. Anyway, they are rumors about problems with some kitsune, you’ve heard of it ?”

OoOoOoOoOoOoOoOoOoOoOoOoOoO

In the backward, the garden of the Yamamoto led to a small shrine, just next to the river. They were indeed a lot of firefly, and maybe some small spirits whose light shined enough for the little human boy to see. 

For now, they were trying to catch a bigger one, a friendly wisp that had been staying around from a long time and didn’t mind children. Tsuna tripped from time to time, but Takeshi may laugh when he did, he was always there to get him up. 

Friends were amazing, decided Tsuna. 

Before starting, they had both given their thanks for the God, and apologies if they were disturbing Them. (They weren’t, they found the children rather fun to watch.)

Then, they tried to play baseball, but it was… pretty impossible. Tsuna could hit and catch to ball, but if he had to run he fell on his face three time out of five. Takeshi, him, played well, but he couldn’t see the ball half the time, and they quickly lost it in the high grass. 

So they played tag. But once again, it was a bit hard for Tsuna. Until he slipped and fell on a slope and rolled in the river. Takeshi ran toward him, worried, but Tsuna’s head got out of the water and he smiled. There were two things that weren’t here before on his head ; two fins were his ears had been. 

Tsuna then looked down, and had a look of realization on his face. 

“Oh no ! I ruined my pants !” he blurted out.

“Hahahahaha, are you alright ?” laughed Takeshi, taken by surprise by the sudden declaration. 

“Oh, yes, no problems ! Look, I’m half-fish !” said Tsuna, lifting his tail so it was partly out of the water and visible from the ground. 

“Woah, that’s so cool ! What happened to your pants ?” exclaimed his friend.

“Well, it got ripped when I turned… Usually I don’t transform with clothes on. At least I have a T-shirt, not one with long sleeves, or my elbow fins would have gotten struck or destroyed it.” explained Tsuna, pointing them with his now scaly and clawed hands. 

“And your shoes and socks ?” asked Takeshi, curious. He had gotten closer to the edge of the water, and was looking fascinated at his friend’s form. He was tempted to touch, so he lifted his arm.

“They fell I think. Wait a second, I’m going to get them.” and he went under, flashing his tail once more as he went down. 

Drops of water almost hit the humain boy, who was leaning above the stream in hopes of seeing Tsuna better. The surface was filled with ripples, and in the night the water was as black as the sky. A flash of light, reflection of the numerous firefly on scales, and a head broke the surface. Tsuna’s hair was, strangely, looking as fluffy as before, like he didn’t just get wet. He had a triumphant smile on his face, and his soggy shoes gripped in his finned hands. 

“There ! I’m not sure if I can wear them anymore, but at least they’re not lost, or polluting the stream. I would hate to upset it’s God or it’s inhabitants. There was fishes and animals I’ve never seen before, and thanks to Mom I know a lot of them !” 

“That’s so cool ! Do you wanna play more ?” asked Takeshi, moving back and forth were he was, barely avoiding falling in.

“Like this ? How ?” answered Tsuna.

“Should I jump in ? I could grab you and you pull me or something. I don’t think we can play tag, I’ve heard mermaids are some of the fastest swimmers. So I’d lose, but there would be no competition, it’s not fun.” Said Takeshi, tilting his head on the side.

“Why not ? I’ll catch you ! But you’re not gonna be too cold, right ? Mom says it’s bad for humans, that if they stay in too long, they can get sleepy, and drown and die. Or that it makes them ill.” worried Tsuna, watching intensely the boy in front of him. 

He moved toward the ground, to gently set his drenched shoes somewhere dry. He also quickly got off him what was left of his pants (sadly unmendable. He liked that pair !).

“I think it’s for when it’s freezing. But we’re in summer now ! So it should be fine. Anyways, Dad told me I’d always be safe in the water, especially in our river, because our God watches over us. And in exchange, we’re priests, we take care of the shrine, and I leave Them riceballs, and mochi.” explained in a serious voice the boy, with a touch of pride at the end. It was obvious that he didn’t mind at all what some would call the burden of his family. 

With that, he carefully got out of his own shoes, leaving them neatly next to Tsuna’s and with a joyful yell, jumped directly where his friend was. The impact with both the water and the merboy knocked his breath out of him, but he didn’t have the time to panic before two arms encircled his waist and hoisted him to the surface. Gasping, he shook his head to get rid of the water in his hair and eyes like a dog (no, a puppy). Opening his warm brown eyes, he turned to look more closely to Tsuna and was met with a small frown. 

Tsuna had been taken by surprise when Takeshi had jumped without warning, and almost missed catching him. He was a bit concerned, it was the first time he saw a human swim up close. Their limbs didn’t look very efficient, and they had no scales to protect themselves from the predators in deep waters. As promised, he carried him, cradling Takeshi close, despite their similar height. After some fumbling, the human ended in a princess hold. They looked at each other, and laughed helplessly. 

“I know how to swim, you don’t have to carry me like that.” said Takeshi, still a little breathless. 

“It’s a bit hard to swim upwards, yes. Maybe you could grab my shoulders or something ? Like that I can go fast, and you can still breathe. What do you think ?” asked Tsuna, shifting so he only held him by the hands. Takeshi was moving his legs to stay afloat, facing him. 

Takeshi nodded enthusiastically at the suggestion, and half climbed on Tsuna’s back when the merboy turned. 

“Ready ?” said Tsuna.

“Of course !” smiled Takeshi, mindful of the scales and fins, but firmly anchored. “Let’s go !”

They shooted up like an arrow, at an impressive speed. It was as if the water was opening before them, they moved effortlessly. The river was narrow, and they were some rocks breaking the surface, but they never touched them, even with how fast they were going. Tsuna’s vision was indeed great in both water and darkness, and he had lightning fast reflexes. He dodged the obstacles in his path, while Takeshi did his best to hold on. It was harder than he thought, but exhilarating at the same time. They turned back, barely slowing down. 

Takeshi had keeped his mouth shut to avoid inhaling water by mistake, but right now, with the adrenaline coursing his veins, he couldn’t hold his delighted laughter in. 

Finally, after going back and forth some more time, they slowed down to an halt. Takeshi’s hair was windswept, wet and his face rosy with laughter. He was rubbing the water out of his eyes and Tsuna had to hold him once more, because he had troubles staying upwards on his own. 

“It was so cool ! We have to do that again !” exclaimed Takeshi, unbothered by the fact that he was in a position most would find embarrassing. But they were both nine, and this kind of thought was far from their minds. (They wouldn’t really care later either.)

Unfortunately, it was time to go home. They could both hear their parent’s calls, asking them to come back to the shop. Tsuna had to haul Takeshi out of the water, now that the excitement had ended the boy was dead on his feet. Tsuna was faring a little better, but he wanted to sleep too. 

To get out of the water was harder than to get in, and he sped enough to have the momentum help him swing on the riverbank. He had to concentrate to get back to him human form, as there was no way to dry. It tingled to revert back, to reabsorb his otherworldly features in his skin, but it didn’t hurt anymore, like it did the first times. 

Carrying his ruined pants and shoes in one hand, bottom bare as the day he was born, he started walking. Guiding the sleepy Takeshi by taking his arm in his free hand, they reached the house and shop. Their parents were waiting for them on the doorstep, with big towels that they immediately used to bundle them up, taking the tired children in their arms. 

“Did you two had fun ?” chuckled Nana, rocking her son a bit while drying his hair. He whined a bit but didn’t move and only buried himself deeper in her embrace. 

“Lots ! Can we come back some time ?” asked Tsuna, turning his eyes to the Yamamoto’s. 

“Of course you can ! You boys are friends aren’t you ? Just maybe not so late next time. Today was an exception, night is for sleeping.” reassured them Tsuyoshi.  
And with a few goodbyes, they left. Tsuyoshi had lended them one of Takeshi’s too small pants. It suited Tsuna, and was far better than stepping outside with nothing on his bottom. He didn’t have shoes either, but it wasn’t much a problem, his mother was carrying him. 

There, safe in her loving arms, he was lulled to sleep by her stride. 

“Let’s hope he doesn’t make an habit of ruining his clothes like that too often.” she pondered. 

She didn’t care about them, but social norms said you had to wear some and they had to avoid standing out. 

“Something that doesn’t tear when he transform… Skirts don’t but humans only approve them on girls, so bothersome. Kilts ? We’re not in the right country for that, and they don’t wear robes either. Why do fashion have to be so complicated ?” She mused it a bit more, until she finally found a solution. 

OoOoOoOoOoOoOoOoOoOoOoOoOoO

The next week, they went shopping and she bought him a few casual kimonos and yukatas, with sandals to complete the look. Not too much because he was still growing and it would be a waste of money. He wouldn’t wear them a lot on weekdays, the school he went to had an uniform. But for the rest of the time, he wouldn’t have to worry about ruining another pair of pants and would be able to play in the waters hidden from human sight. (They weren’t that rare in Nanimori, and Nana was on good terms with the majority of the water related beings.) 

As for Tsuna, he was overjoyed to finally have a true friend. Takeshi was kind, full of energy, and even if he was popular at school an Tsuna wasn’t, he still took time to play with him at recess. The human boy’s other friend weren’t happy, but Takeshi made it clear that he didn’t want to stay with those that bothered the outcast. Some left, the other grumbled but did as he asked. 

It wasn’t rare for the young boys to go to one of their home after school to play more, or to do homework together. They weren’t very good at it, and got easily distracted, but with the aid of their parents they always managed to complete it. It was the condition for the visits, it couldn’t distract them too much from their school work, and they had to do it before going to the river. 

They were full of joy and free of worry, and life was good. They would have some peaceful years more like this one before things changed.

**Notes for the Chapter:**

> The updates will stay irregular, it's mostly a little story made of drabbles and I'm bad at keeping a shedule. 
> 
> I know what most of the other characters are (and they probably won't all be supernatural) so you can amuse yourself by guessing who will be what. 
> 
> A-F

**Author's Note:**

> Find me on my tumblr ; [Ambroise-Framboise](https://ambroise-framboise.tumblr.com/) !  
> 


End file.
